Most prior grape-picking machines use practically the same principle for harvesting grapes. This is to beat or shake the vine by imparting sinusoidal or pseudo-sinusoidal motion thereto at an amplitude and at a frequency suitable for causing the grapes or the bunches of grapes to become detached. This motion is communicated to the vine via shaker or beater members. disposed in such a manner as to act either on the vinestock or stem or else on the vegetation, i.e. on the fruit-bearing portion of the vine, depending on the type and number of shaker or beater members used. The percentage of bunches and/or individal grapes which are detached from the vine depends on the number and the amplitude of the oscillations to which a given bunch of grapes is subjected. The more energetic the shaking to which a given bunch of grapes is subjected, and the more frequently it is shaken, the more likely said bunch or its individual grapes is/are to become detached from the vine. The number and the amplitude of the oscillations to which a given bunch of grapes is subjected depend on various parameters that may be selected, in particular on the amplitude and the frequency of the control mechanism associated with the shaker or beater members, on the length of the active zone of said shaker or beater members, on the stiffness or the flexibility thereof, and on the speed at which the machine advances, together with other factors which are imposed by the vine itself, in particular the way it is trained, its shape, and the resistance it gives to the motions of the beater or shaker members. In any event, in order to obtain a high percentage of harvested individual grapes or bunches of grapes, it is important for all of the bunches of grapes at all levels on the vegetation to be properly subjected to the action of the shaker members.
In prior art picking machines of the above-indicated type (French Patent Nos. 2 516 742 and 2 522 246), each beater in each of two sets of beaters is constituted by a metal rod of the piano wire type, with both ends of the rods being fixed rigidly to one of two vertical and longitudinal supports in the form of a frame, and with each support frame being hinged to the chassis of the machine about a vertical axis which is situated close to one of its ends (French Patent No. 2 516 742) or else which is movably mounted on the chassis by means for maintaining the two support frames permanently in mutually parallel positions as they perform oscillating motion (French Patent No. 2 522 246). However, although the beaters are intended to be made of piano wire, their capabilities in elastic deformation and consequently their capabilities in adapting to variations in thickness of vine vegetation or in the machine being misaligned relative to a row or vines are relatively poor. This is so much the case that in French Patent No. 2 516 742 provision is made for each support frame to be fixed via its associated control mechanism to the bottom end of a vertical arm whose top end is hinged to the chassis of the machine about both a horizontal axis and a longitudinal axis. Each arm is returned to a vertical position by the combined effect of a mass and a spring. With such an assembly, in addition to their reciprocating transverse motion under the action of the control mechanism, both support frames and both associated sets of beaters move away from each other and towards each other automatically as a function of varying thickness of vine vegetation as the machine moves along a row of vines. However this adaptation of the gap between the two sets of beaters to the variation in the thickness of the vegetation is performed simultaneously by all of the beaters in each set. Consequently, when the beaters pass a vine plant whose vegetation varies considerably in thickness in the vertical direction, the gap between the two sets of beaters adjusts automatically to the thickest portion of the vegetation of the vine plant. As a result, the beaters level with the thinner portions of the vegetation have little or no effect on these portions of the vegetation and only a small quantity of the grapes thereon are harvested, if any.
The main object of the present invention is therefore to provide a harvesting machine of the above-indicated type in which the rod-shaped shaker members are capable of adapting individually to variations in the thickness of the vegetation of fruit trees and bushes so that the shaking is effective at all levels of the vegetation.